Microstimulator having self-contained power source

ABSTRACT

An implantable microstimulator configured to be implanted beneath a patient&#39;s skin for tissue stimulation to prevent and/or treat various disorders, e.g., neurological disorders, uses a self-contained power source such as a primary battery, a rechargeable battery, or other energy sources. For the rechargeable battery, and other energy sources that may require a periodic or occasional replenishment, such recharging or replenishment is accomplished, for example, by inductive coupling with an external device. A suitable bidirectional telemetry link allows the microstimulator system to inform the patient or clinician regarding the status of the system, including the charge level of the power source, and stimulation parameter states. Processing circuitry within the microstimulator automatically controls the applied stimulation pulses to match a set of programmed stimulation parameters established for a particular patient. The microstimulator preferably has a cylindrical hermetically sealed case having a length no greater than about 27 mm and a diameter no greater than about 3.3 mm. A reference electrode is located on one end of the case and an active electrode is located on the other end of the case. Further, the case is externally coated on selected areas with conductive and non-conductive materials.

[0001] The present application claims the benefit of U.S. ProvisionalPatent Application Serial No. 60/392,475, filed Jun. 28, 2002, whichapplication is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] The present invention relates generally to the field ofimplantable medical devices and more particularly to microstimulatordevices incorporating a self-contained power source, such as a primarybattery or a rechargeable battery, for powering the internal electroniccircuitry.

BACKGROUND OF THE INVENTION

[0003] Implantable microstimulators, also known as BION® devices (whereBION® is a registered trademark of Advanced Bionics Corporation, ofSylmar, Calif.), are typically characterized by a small, cylindricalhousing which contains electronic circuitry that produces electriccurrents between spaced electrodes. These microstimulators are implantedproximate to target tissue, and the currents produced by the electrodesstimulate the tissue to reduce symptoms or otherwise provide therapy forvarious disorders. An implantable battery-powered medical device may beused to provide therapy for various purposes including nerve or musclestimulation. For example, urinary urge incontinence may be treated bystimulating the nerve fibers proximal to the pudendal nerves of thepelvic floor; erectile or other sexual dysfunctions may be treated byproviding stimulation of the cavernous nerve(s); and other disorders,e.g., neurological disorders caused by injury or stroke, may be treatedby providing stimulation of other appropriate nerve(s).

[0004] Implantable microstimulators have been disclosed that providetherapy for neurological disorders by stimulating the surrounding nervesor muscles. Such devices are characterized by a sealed housing whichcontains electronic circuitry for producing electric currents betweenspaced electrodes. A microstimulator is precisely implanted proximate tothe target tissue area and the electrical currents produced at theelectrodes stimulate the tissue to reduce the symptoms and otherwiseprovide therapy for the neurological disorder.

[0005] A battery-powered microstimulator of the present invention ispreferably of the type referred to as a BION® device, which may operateindependently, or in a coordinated manner with other implanted devices,or with external devices.

[0006] By way of example, in U.S. Pat. No. 5,312,439, entitledImplantable Device Having an Electrolytic Storage Electrode, animplantable device for tissue stimulation is described. U.S. Pat. No.5,312,439 is incorporated herein by reference. The describedmicrostimulator shown in the '439 patent relates to an implantabledevice using one or more exposed, electrolytic electrodes to storeelectrical energy received by the implanted device, for the purpose ofproviding electrical energy to at least a portion of the internalelectrical circuitry of the implantable device. It uses an electrolyticcapacitor electrode to store electrical energy in the electrode whenexposed to body fluids.

[0007] Another microstimulator known in the art is described in U.S.Pat. No. 5,193,539, “Implantable Microstimulator”, which patent is alsoincorporated herein by reference. The '539 patent describes amicrostimulator in which power and information for operating themicrostimulator is received through a modulated, alternating magneticfield in which a coil is adapted to function as the secondary winding ofa transformer. The induction coil receives energy from outside the bodyand a capacitor is used to store electrical energy which is released tothe microstimulator's exposed electrodes under the control of electroniccontrol circuitry.

[0008] In U.S. Pat. Nos. 5,193,540 and 5,405,367, which patents areincorporated herein by reference, a structure and method of manufactureof an implantable microstimulator is disclosed. The microstimulator hasa structure which is manufactured to be substantially encapsulatedwithin a hermetically-sealed housing inert to body fluids, and of a sizeand shape capable of implantation in a living body, with appropriatesurgical tools. Within the microstimulator, an induction coil receivesenergy from outside the body requiring an external power supply.

[0009] In yet another example, U.S. Pat. No.6,185,452, which patent islikewise incorporated herein by reference, there is disclosed a deviceconfigured for implantation beneath a patient's skin for the purpose ofnerve or muscle stimulation and/or parameter monitoring and/or datacommunication. Such a device contains a power source for powering theinternal electronic circuitry. Such power supply is a battery that maybe externally charged each day. Similar battery specifications are foundin U.S. Pat. No. 6,315,721, which patent is additionally incorporatedherein by reference.

[0010] Other microstimulator systems prevent and/or treat variousdisorders associated with prolonged inactivity, confinement orimmobilization of one or more muscles. Such microstimulators are taught,e.g., in U.S. Pat. Nos. 6,061,596 (Method for Conditioning PelvisMusculature Using an Implanted Microstimulator); 6,051,017 (ImplantableMicrostimulator and Systems Employing the Same); 6,175,764 (ImplantableMicrostimulator System for Producing Repeatable Patterns of ElectricalStimulation; 6,181,965 (Implantable Microstimulator System forPrevention of Disorders); 6,185,455 (Methods of Reducing the Incidenceof Medical Complications Using Implantable Microstimulators); and6,214,032 (System for Implanting a Microstimulator). The applicationsdescribed in these additional patents, including the power chargingtechniques, may also be used with the present invention. The '596, '017,'764, '965, '455, and '032 patents are incorporated herein by reference.

[0011] It is also known in the art to use thermal energy to power an atleast partially implantable device, as taught in U.S. Pat. No.6,131,581, also incorporated herein by reference, wherein an implantablethermoelectric energy converter is disclosed.

[0012] Despite the various types of microstimulators known in the art,as illustrated by the examples cited above, significant improvements arestill possible and desirable, particularly relative to a microstimulatorwith a self-contained primary or rechargeable battery that: (a) canaccommodate the various needs of a microstimulator; (b) can accommodatevarious locations in the implanted site; and/or (c) can allow themicrostimulator to operate longer between charges or replacement.

SUMMARY OF THE INVENTION

[0013] The present invention addresses the above and other needs byproviding a battery-powered microstimulator intended to provide therapyfor neurological disorders such as urinary urge incontinence by way ofelectrical stimulation of nerve fibers in the pudendal nerve; to treatvarious disorders associated with prolonged inactivity, confinement, orimmobilization of one or more muscles; to be used as therapy forerectile dysfunction and other sexual dysfunction; as a therapy to treatchronic pain; and/or to prevent or treat a variety of other disorders.The invention disclosed and claimed herein provides such abattery-powered microstimulator and associated external components.

[0014] Stimulation and control parameters of the implantedmicrostimulator are preferably adjusted to levels that are safe andefficacious with minimal discomfort. Different stimulation parametershave different effects on neural tissue, and parameters may be chosen totarget specific neural populations and to exclude others. For example,relatively low frequency neurostimulation (i.e., less than about 50-100Hz) may have an excitatory effect on surrounding neural tissue, leadingto increased neural activity, whereas relatively high frequencyneurostimulation (i.e., greater than about 50-100 Hz) may have aninhibitory effect, leading to decreased neural activity.

[0015] In accordance with certain embodiments of the invention, there isprovided a microstimulator sized to contain a self-contained powersource, e.g., a primary battery. In another embodiment, theself-contained power source comprises a battery which is rechargeable byan external power source, e.g., an RF link, an inductive link, or otherenergy-coupling link. In yet other embodiments, the power source maycomprise other energy sources, such as a super capacitor, a nuclearbattery, a mechanical resonator, an infrared collector (receiving, e.g.,infrared energy through the skin), a thermally-powered energy source(where, e.g., memory-shaped alloys exposed to a minimal temperaturedifference generate power), a flexural powered energy source (where aflexible section subject to flexural forces is placed in the middle ofthe long, thin-rod shape of the microstimulator), a bioenergy powersource (where a chemical reaction provides an energy source), a fuelcell (much like a battery, but does not run down or require recharging,but requires only a fuel), a bioelectrical cell (where two or moreelectrodes use tissue-generated potentials and currents to captureenergy and convert it to useable power), an osmotic pressure pump (wheremechanical energy is generated due to fluid ingress), or the like.

[0016] For purposes of the present invention, the term “self contained”means implanted within the patient and not totally dependent uponexternal (non implanted) sources of energy. Typically, the selfcontained power source will be contained within a housing, e.g., thesame housing as the one that contains the electronic circuits of theimplantable device, that is implanted within the patient or user of thedevice. A key feature of the self contained power source is that it isnot dependent upon a continuous source of external (non-implanted)power. The self-contained power source used with the invention may relyupon an occasional use of an external power source, e.g., an occasionalburst or infrequent injection of energy to replenish the self containedpower source, such as a rechargeable battery or super capacitor, but the“self contained” power source may thereafter operate on its own toprovide needed power for operation of the device without being connectedor coupled to the external source of power.

[0017] In accordance with various embodiments of the invention, there isprovided a microstimulator with at least two electrodes for applyingstimulating current to surrounding tissue and associated electronicand/or mechanical components encapsulated in a hermetic package madefrom biocompatible material. The internal components are powered by theinternal power source. The internal power source is, in one preferredembodiment, a primary battery, and in another preferred embodiment, arechargeable battery. In other embodiments, the energy source may takethe form of any of the various energy sources mentioned above, orcombinations thereof.

[0018] Some embodiments of the invention provide a microstimulator withmeans for receiving and/or transmitting signals via telemetry, such asmeans for receiving and/or storing electrical power within themicrostimulator and for receiving and/or transmitting signals indicatingthe charge level of the internal battery. Certain embodiments of theinvention provide a microstimulator implantable via a minimal surgicalprocedure and the associated surgical tools.

[0019] Methods of manufacturing/assembling the components within themicrostimulator, including the internal battery or other power source,ferrite material, induction coil, storage capacitor, and othercomponents using e.g., conductive and non-conductive adhesives, aredescribed herein. Also described herein are methods of externallycoating the hermetically sealed cylindrical housing to protect theinternal components.

[0020] Embodiments described herein may include some or all of the itemsmentioned above. Additional embodiments will be evident upon furtherreview of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other aspects of the present invention will be moreapparent from the following more particular description thereof,presented in conjunction with the following drawings wherein:

[0022]FIG. 1 is a block diagram for an exemplary battery-powered BION(BPB) system made in accordance with the present invention;

[0023]FIG. 2 shows a representative biphasic electrical currentstimulation waveform that may be produced by the battery-powered BIONsystem of the present invention;

[0024]FIG. 3 shows a table summarizing exemplary battery-powered BIONstimulation parameters;

[0025]FIG. 4 is an enlarged side view showing the overall descriptivedimensions for the battery-powered BION case, the battery, and theelectronic subassembly;

[0026]FIG. 5 is a perspective view of the battery and connecting wires;

[0027]FIG. 6 is a block diagram representing the battery states based onmeasured battery voltage;

[0028]FIG. 7 is a front view of a representative remote control panelshowing exemplary front panel components;

[0029]FIG. 8 is an exploded view of the internal components of the BPBdevice;

[0030]FIG. 9 is a perspective top view of the internal electronic panelin a batch configuration;

[0031]FIG. 10 is a perspective top view of the panel shown in FIG. 9with the integrated circuitry attached;

[0032]FIG. 11A is a perspective top view of the panel shown in FIG. 9with the integrated circuitry shown in FIG. 10 and with the topcapacitors and diodes attached;

[0033]FIG. 11B is an enlarged detailed view of a portion of FIG. 11A,showing in greater detail the attachment of the top capacitors anddiodes;

[0034]FIG. 12 is a perspective top view of the panel shown in FIG. 9with the integrated circuitry shown in FIG. 10, the top capacitors anddiodes shown in FIG. 11A, and with the top ferrite half attached;

[0035]FIG. 13 is an enlarged detail view of the assembled componentsshown in FIG. 12 depicting the connecting electrical wires;

[0036]FIG. 14A is a perspective top view of a sub-assembly assembledduring the manufacturing operation;

[0037]FIG. 14B is a bottom perspective view of the sub-assembly shown inFIG. 14A;

[0038]FIG. 14C is a top plan view of the sub-assembly shown in FIG. 14A;

[0039]FIG. 14D is a bottom plan view of the sub-assembly shown in FIG.14A;

[0040]FIG. 15A is a perspective top view of the sub-assembly shown inFIG. 14A with a coil wound on the middle section of the ferritecylinder;

[0041]FIG. 15B is a cross-section view of the sub-assembly shown in FIG.15A taken along line 15B-15B;

[0042]FIG. 15C is a top view of the sub-assembly shown in FIG. 14A withthe coil ends depicted;

[0043]FIG. 16 is an enlarged detail perspective view of the sub-assemblyshown in FIG. 15A placed in a soldering fixture;

[0044]FIG. 17 is an exploded view of carrier fixture plates;

[0045]FIG. 18 is a perspective view of a supporting work-plate with oneof the carrier plates shown in FIG. 17 and the sub-assembly shown inFIG. 15A;

[0046]FIG. 19 is a perspective view of the sub-assembly shown in FIG.15A with a battery attached and also depicting assembled internalcomponents of a BPB device of the present invention;

[0047]FIG. 20A is a top view of a BPB device of the present inventionshowing external coatings;

[0048]FIG. 20B is a cross-sectional view taken along line 20B-20B shownin FIG. 20A;

[0049]FIG. 20C is an end view of the BPB device shown in FIG. 20A; and

[0050]FIG. 21 is an exemplary circuit block diagram showing the mainimplantable components and their interactions of one embodiment of theinvention.

[0051] Corresponding reference characters indicate correspondingcomponents throughout the several views of the drawings.

DETAILED DESCRIPTION OF THE INVENTION

[0052] The following description is of the best mode presentlycontemplated for carrying out the invention. This description is not tobe taken in a limiting sense, but is made merely for the purpose ofdescribing the general principles of the invention. The scope of theinvention should be determined with reference to the claims.

[0053] A fully assembled battery-powered microstimulator (also referredto as a BION® microstimulator, or battery-powered BION (“BPB”) device)made in accordance with the present invention may operate independently,or in a coordinated manner with other implanted devices, or withexternal devices.

[0054] The BPB device is a pulse generator which includes an internalpower source. Regardless of whether the internal power source comprisesa primary battery, a rechargeable battery, or an alternative powersource as described below, the device containing the internal powersource will be referred to as a “BPB” device for purposes of the presentinvention.

[0055] In one preferred embodiment, the power source comprises arechargeable battery. The battery is recharged, as required, from anexternal battery charging system, typically through an inductive link.

[0056] In another preferred embodiment, the power source comprises aprimary battery. A primary battery, or primary battery cell, offers theadvantage of typically having five to ten times more energy density thandoes a rechargeable battery. Further, a primary battery typicallyexhibits a much lower self-leakage than does a rechargeable battery.

[0057] In other embodiments of the invention, the power source of theBPB device comprises an alternative energy source, or a combination ofalternative energy sources. One siuch alternative energy source is asuper capacitor. A super capacitor typically has ten times less energydensity than does a rechargeable battery, but it can be recharged veryquickly, thus allowing for the use of a simple combination RC andcharger system. Additionally, power coupled inductively to a supercapacitor storage element may enable pulsed radio frequency (RF) powerto be used, rather than continuous RF power. A super capacitor istypically used, most advantageously, in combination with another powersource, such as a primary battery or a rechargeable battery. The supercapacitor may be charged rapidly, and then the charge stored on thesuper capacitor is available to supplement operation of the BPB device,either directly (to assist with higher energy stimulation levels orpower requirements), or indirectly (to help recharge the battery).

[0058] A further alternative energy source that may be used with the BPBdevice of the invention is a nuclear battery, also known as an atomicbattery. Recent developments have indicated that, e.g., amicro-electro-mechanical system (MEMS) nuclear battery is capable ofdelivering significant amounts of power. These power sources areextremely small, and may be combined or grouped together, as required,in order to provide the needed power to operate the BPB device.

[0059] Still another alternative energy source that may be used with theBPB device is a mechanical resonator. Generating power from mechanicalresonators and normal human movement has long been practiced in the art,e.g., with wrist-watches, and MEMS versions of such resonators have beenaround for a number of years. However, to applicants' knowledge, the useof MEMS mechanical resonators has never been applied to implantabledevices, such as the BPB device of the present invention.

[0060] A further alternative energy source for use with a BPB device isan infrared collector, or infrared (solar) power source. Because theskin and body tissue is relatively transparent to red and infraredlight, it is possible, e.g., through the use of an implanted siliconphotovoltaic cell, to collect sufficient energy to power the BPB devicefrom an external infrared source, such as the sun.

[0061] Yet an additional alternative energy source for use with the BPBdevice of the present invention is a thermally-powered energy source.For example, thermal difference engines based on memory shape alloyshave been demonstrated to be very efficient engines capable ofgenerating power with minimal temperature differences. Hence, byincorporating such a thermal difference engine within the BPB device, aninternal energy source is provided that derives its energy from a smalltemperature difference, e.g., the temperature difference between thesurface of the skin and a location 2-3 cm deeper inside the body.

[0062] Still another alternative energy source is a flexural poweredenergy source. The BPB device has the general shape of a long thin rod.Hence, by placing a flexible section in the middle of the device, suchsection will be subjected to flexural forces. Such flexural forces, whenapplied to a suitable piezoelectric element coupled to the flexiblesection, will generate piezoelectric bimorphs which may be used togenerate a voltage (power). Such technique has been used to generatepower from wind.

[0063] Another alternative energy source is a bioenergy power source. Ina bioenergy power source, a chemical reactor interacts with constituentsto produce mechanical or electrical power.

[0064] A fuel cell represents another type of alternative energy sourcethat may be used with the BPB device. A fuel cell, in principle,operates much like a battery. Unlike a battery, however, a fuel celldoes not run down or require recharging. Rather, it produces energy inthe form of electricity and heat as long as fuel is supplied. A fuelcell system which includes a “fuel reformer” can utilize the hydrogenfrom any hydrocarbon fuel. Several fuel cell technologies may be usedwith the BPB device of the present invention, such as Phosphoric Acid,Proton Exchange Membrance or Solid Polymer, Molten Carbonate, SolidOxide, Alkaline, Direct Methanol, Regenerative, Zinc Air, or ProtonicCeramic. Such fuel cells may be designed for a single use, orrefillable.

[0065] Yet an additional alternative energy source that may be used withthe BPB device is a bioelectrical cell. In a bioelectrical cell, a setof electrodes (two or more) is implanted in the body tissue. Theseelectrodes sense and use tissue generated potentials and currents inorder to power the BPB device. Tissue such as cardiac muscle, cardiacconducting cells and neural tissue are examples of tissue that generateselectrical potentials and currents. In a particular case, specializedbiological tissue may be implanted to provide the energy. The implantedbiological tissue remains alive due to the environment provided by thebody where it is implanted.

[0066] A further alternative energy source that may be used with the BPBdevice of the present invention is an osmotic pressure pump. Osmoticpressure pumps may be used to generate mechanical energy due to water,or other fluid, ingress. This mechanical energy may then be used togenerate other forms of energy, such as electrical energy. For example,osmotic pressure may be used to separate the plates of a capacitor. Asthe plates of the capacitor separate with a given amount of charge dueto osmotic pressure, the energy stored in that capacitor is incremented.

[0067] In the description of the BPB device that follows, the powersource used within the BPB device is described as a rechargeablebattery. However, it is to be understood, as previously indicated, thatthe “power source” used within the BPB device may take many forms,including a primary battery or the alternative power sources enumeratedabove, and that when the term “battery” or “power source” is usedherein, such terms, unless otherwise indicated, are meant to broadlyconvey a source of energy or power contained within, or coupled to, theBPB device.

[0068] The BPB device preferably has a substantially cylindrical shape,although other shapes are possible, and at least portions of the BPBdevice are hermetically sealed. The BPB device includes a processor andother electronic circuitry that allow it to generate stimulus pulsesthat are applied to a patient through electrodes in accordance with aprogram that may be stored, if necessary or desired, in programmablememory.

[0069] The BPB device circuitry, power source capacity, cycle life,hermeticity, and longevity provide implant operation at typical settingsfor at least five years. Battery or power source) control circuitryprotects the battery or other power source from overcharging, ifrecharging is needed, and operates the BPB device in a safe mode uponenergy depletion, and avoids any potentially endangering failure modes,with a zero tolerance for unsafe failure or operational modes. The BPBdevice accepts programming only from compatible programming devices.

[0070] The publications and patents listed in the table below, which areall incorporated herein by reference, describe various uses of theimplantable BPB device for the purpose of treating various neurologicalconditions: Application/ Filing/ Patent/ Publication Publication No.Date Title U.S. Pat. No. Issued Method for Conditioning Pelvic 6,061,596May 9, 2000 Musculature Using an Implanted Microstimulator U.S. Pat. No.Issued Structure and Method of Manufacture 5,193,540 Mar 16, 1993 of anImplantable Microstimulator PCT Publication Published ImplantableStimulator System and WO Jan 13, 2000 Method for Treatment of Urinary00/01320 Incontinence PCT Publication Published System and Method forConditioning WO May 29, 1997 Pelvic Musculature Using an 97/18857Implanted Microstimulator

[0071] The implantable BPB system of the present invention, inaccordance with some embodiments, includes internal and externalcomponents, as well as surgical components, as shown in FIG. 1. Theinternal components 10′ are implanted in the target tissue area of thepatient and the external components 20 are used to recharge or replenish(when recharge or replenishment is needed) and communicate with theinternal components. The components shown in FIG. 1 represent as a wholean implantable BION® microstimulator system 100. It should be noted thatthe present invention is not directed to a specific method for treatinga disorder, but rather describes possible BPB configurations, methods ofmanufacture, and how the implantable BPB system functions in conjunctionwith the components shown in FIG. 1.

[0072] A block diagram that illustrates the various components of theBPB system 100 is depicted in FIG. 1. These components may be subdividedinto three broad categories: (1) implantable components 10′, (2)external components 20, and (3) surgical components 30.

[0073] As seen in FIG. 1, the BPB device 10 includes a case 12; battery16; BPB electronic subassembly 14, which includes BPB coil 18 and astimulating capacitor C_(STIM) 15; indifferent/reference electrode 24;and active/stimulating electrode 22. The block diagram shown in FIG. 21also shows the main implantable components of the BPB device 10 andtheir interactions.

[0074] The external components 20, shown in FIG. 1 include chargingsystem 39, which consists of the chair pad 32 and the base station 50; aremote control 40; and a clinician's programmer 60. The chair pad 32 hasa recharger coil 34 which is electrically connected to (or may be partof) the base station 50 with extension 36 and communicates with the BPBelectronic subassembly 14 with a bidirectional telemetry link 48. Thebase station 50 has an external medical grade AC adapter which receivesAC power 52 through extension 54. The remote control 40 sends andreceives communication from/to the base station 50 through Infrared DataAssociation, IrDA interface 42. (IrDA is a standard for transmittingdata via infrared light.) The remote control 40 also communicates withthe clinician's programmer 60 through an IrDA interface 44 andcommunicates with the BPB electronic subassembly 14 with an RF telemetryantenna 46 through the bidirectional telemetry link 48. The clinician'sprogrammer 60 may also communicate with the BPB electronic subassembly14 through the bidirectional telemetry link 48. The base station 50 alsocommunicates with the clinician's programmer 60 through an IrDAinterface 45. The bidirectional telemetry link 48 is also known as theFSK (Frequency Shift Key) telemetry link, or RF telemetry link. Inaddition, the charging system 39 has a forward telemetry link 38. Suchlink may use OOK-PWM (On/Off Keying—Pulse Width Modulation), and istypically an inductive telemetry link. When used, both power andinformation may be transferred to the BPB device. When charging is notneeded, e.g., when the battery comprises a primary battery, such aninductive link may still be used to transfer information and data to theBPB device.

[0075] The surgical components 30 illustrated in FIG. 1 include the BPBimplant tools 62 and an external neurostimulator 64. The implantable BPBdevice 10 is inserted through the patient's tissue through the use ofappropriate surgical tools, and in particular, through the use oftunneling tools, as are known in the art, or as are specially developedfor purposes of implantable BPB stimulation systems.

[0076]FIG. 1 represents the BPB system 100 as a block diagram which aidsin simplifying each of the described implantable components 10′,external components 20, and surgical components 30. A betterunderstanding of the possible functions associated with every element ofthe internal components 10′, external components 30, and surgicalcomponents 30 is provided in the details that follow.

[0077] Turning next to FIG. 2, an exemplary waveform is shown thatillustrates some of the BPB biphasic electric current stimulationparameters. Other parameters not shown include burst, ramp, and dutycycles. The BPB device 10 may produce, for instance, an asymmetricbiphasic constant-current charge-balanced stimulation pulse, as shown inFIG. 2. Charge-balancing of the current flow through the body tissue inboth directions is important to prevent damage to the tissue whichresults from continued preponderance of current flow in one direction.The first phase of the stimulation pulse is cathodic and the secondphase (recharge phase) utilizes an anodic charge recovery to facilitatea charge balance. The stimulation phase current amplitude 66 isprogrammable from 0.0 to about 10 mA, for instance, in 0.2 mAincrements. To prevent patient discomfort due to rapidly increasing ordecreasing amplitudes in the first phase of the waveform (of stimulationamplitude 66), changes in amplitude occur smoothly over a transitionperiod programmable by adjusting the allowed slope (step sizeincrements) of the amplitude through continuous pulses.

[0078] The stimulation capability of the BPB device 10 is depicted bythe stimulation parameters specified in the table shown in FIG. 3. Theseparameters may be achieved by the electronic subassembly 14, battery (orother power source) 16, and electrodes 22 and 24. The stimulatingelectrode 22 is coupled to the electronic subassembly 14 with astimulating capacitor C_(STIM) 15. Net DC charge transferred duringstimulation is prevented by the capacitive coupling provided by thestimulating capacitor 15, between the BPB electronic subassembly 14 andthe stimulation electrode 22. During the first phase of the pulsewaveform shown in FIG. 2, the BPB stimulation electrode 22 has acathodic polarity with associated negative current amplitude, and thereference electrode 24 is the anode.

[0079] Each BPB device 10 has an identification code used to uniquelyidentify the device. The identification code allows each unit to act onparticular messages containing its unique identification code. Each BPBdevice 10 also responds to universal identification codes used for casesin which the unique address is unknown by the external device, theunique address has been corrupted, or when a command is sent to multipleBPB units.

[0080] Referring back to FIG. 1, the BPB device 10 receives commands anddata from the remote control 40, clinician's programmer 60, and/orcharging system 39 via FSK (frequency shift keying) telemetry link 48.The range of the FSK telemetry link 48 is no less than 30 cm in anoptimal orientation. Factors that may affect the range of the FSKtelemetry link 48 include an impaired BPB device, depleted externaldevice, insufficient power, environmental noise, and other factors,e.g., the surroundings. When a request is sent to the BPB device 10 bythe clinician's programmer 60, the remote control 40, or the chargingsystem 39, the maximum response time for the FSK telemetry link 48 isless than 2 seconds, under normal operating conditions.

[0081] The OOK (On-Off Keying) telemetry link 38, shown in FIG. 1,allows commands and data to be sent by the charging system 39 to the BPBdevice 10. The range of the OOK telemetry link 38, is ideally no lessthan 15 cm in any orientation and no less than 15 cm in an optimalorientation. The OOK telemetry link 38 allows the charging system 39 tocommunicate with the BPB device 10 even when the BPB device 10 is notactively listening for a telemetry signal, e.g., when the BPB device 10is in the Hibernation State or the Storage State (states for the BPBdevice which will be discussed in detail below). The OOK-PWM telemetrylink 38 will also provide a communication interface in an emergencysituation, e.g., an emergency shutdown.

[0082] Reverse telemetry is also available through the FSK telemetrylink 48. The reverse FSK telemetry link 48, allows information to bereported by the BPB device 10 to the clinician's programmer 60, theremote control 40, and/or the charging system 39. The range of thereverse telemetry link 48 is no less than 30 cm in an optimalorientation. The type of information transmitted from the BPB device 10to the clinician's programmer 60, remote control 40, and/or chargingsystem 39, may include but is not limited to battery voltage, BPBinternal register settings, and acknowledgments.

[0083] The FSK telemetry system, in one preferred embodiment, operatesin the frequency band of 127 KHz±8 KHz. When the BPB device 10 hasreceived a valid (i.e. non-error containing) message, an acknowledgmentis transmitted.

[0084] There will be times when the messages sent in either direction onthe telemetry link will not be received by the intended recipient. Thismay be due to range, orientation, noise, or other problems. The severityof the problem will determine the appropriate response of the system.For example, if a programming change is made by the clinician'sprogrammer 60 and a response is expected by the clinician's programmer60 from the BPB device 10, the clinician's programmer 60 attempts to geta response from the BPB device 10 until a satisfactory response isreceived, or until a reasonable number of attempts are made. If nosatisfactory response is obtained, this might indicate that the BPBdevice 10 does not have sufficient power in its internal battery 16 tomake a response, in which case charging should be attempted by the user(if the battery 16 is a rechargeable battery). Events such as these arelogged for future diagnostic analysis. Error messages are displayed onthe clinician' programmer 60, the remote control 40, and/or the basestation 50, in response to an abnormal response to telemetrycommunication. When an invalid command is received by BPB device 10, noaction occurs. All valid commands are executed by the BPB device 10within 1 second after receiving a command, under normal operatingconditions.

[0085] Referring now to FIG. 4, a side view of the BPB case 12 is showndepicting exemplary overall dimensions for the case 12 and BPB internalcomponents. The BPB case 12 functions together with the additionalcomponents of BPB device 10, including the BPB battery 16 and the BPBelectronic subassembly 14. As shown in the figures, BPB case 12 may havea tubular or cylindrical shape with an outer diameter shown in FIG. 4 asD1 having a minimum value of about 3.20 mm and a maximum value of 3.7mm, and preferably a maximum value of about 3.30 mm. The inner diameterof the portion of the BPB case 12 enclosing the electronic subassembly14 is shown in FIG. 4 as D2 with a minimum value of about 2.40 mm and amaximum value of about 2.54 mm. The inner diameter of the portion of theBPB case 12 enclosing the BPB battery 16 is shown in FIG. 4 as D3 with aminimum value of about 2.92 mm and a maximum value of about 3.05 mm. Thelength of the BPB case 12 is shown in FIG. 4 as L1 with and is nogreater than about 30 mm, and preferably no greater than about 27 mm (L1includes the length of the case housing plus the stimulating electrode22). The length L2 of the case 12 has a value of about 24.5 mm. Theportion of the case 12 enclosing the electronic subassembly 14 is shownin FIG. 4 as length L3 with a maximum value of about 13.00 mm. Theportion of the case 12 enclosing the BPB battery (or other power source)16 is shown in FIG. 4 as length L4 with a value of about 11.84 mm. Thesedimensions are only exemplary, and may change, as needed or desired toaccommodate different types of batteries or power sources. For example,the BPB device, instead of being cylindrically shaped, may have arectangular or oval cross section having a width and height that is nogreater than about 3.3 mm, and an overall length is no greater thanabout 27 mm. To help protect the electrical components inside the BPBdevice 10, the case 12 of the BPB device 10 is hermetically sealed. Foradditional protection against, e.g., impact, the case 12 may be made ofmetal (e.g., titanium), which material is advantageously biocompatible.The BPB case 12 is preferably, but not necessarily, Magnetic ResonanceImaging (MRI) compatible. The manufacturing/assembly process of the BPBdevice 10 will be discussed in detail below.

[0086] The BPB device 10 includes a battery 16. The battery 16 may be aprimary battery, a rechargeable battery, or other power source, aspreviously described. When the battery 16 is rechargeable, it isrecharged, as required, from an external battery charging system 39typically through the OOK-PWM telemetry link 38 (as shown in FIG. 1).

[0087] The BPB device 10 includes a processor and other electroniccircuitry that allow it to generate stimulating pulses that are appliedto a patient through electrodes 22 and 24 in accordance with a programstored in programmable memory located within the electronic subassembly14.

[0088] The battery 16 shown in FIG. 5 is a self-contained battery whichpowers the BPB device 10. The battery 16 may be a Lithium-ion battery orother suitable type of battery or power source. One type of rechargeablebattery that may be used is disclosed in International Publication WO01/82398 A1, published 01 Nov. 2001, and/or WO 03/005465 A1, published16 Jan. 2003, which publications are incorporated herein by reference.Other battery construction techniques that may be used to make thebattery 16 used with the BPB device are as taught, e.g., in U.S. Pat.Nos. 6,280,873; 6,458,171 and U.S. Publications 2001/0046625 A1 and U.S.2001/0053476 A1, which patents and publications are also incorporatedherein by reference. Recharging (when needed) occurs from an externalcharger to an implant depth, e.g., up to 13.87 cm. At this distance,charging from 10% to 90% capacity can occur in no more than eight hours.The battery 16 functions together with the additional components of theBPB device 10, including the BPB case 12 and the BPB electronicsubassembly 14 to provide electrical stimulation through the electrodes22 and 24. The battery or power source 16 has a pin 95 protruding fromthe flat end for the positive polarity contact. This pin has aprotruding length, e.g., of 0.25 mm and is embedded internallythroughout the length of the cathode case of the battery 16. The pin 95may be made of platinum or other suitable anode material. Wires 68A and68B are used for connecting the battery 16 to the electronic subassembly14. Wire 68A is insulated and laser welded or otherwise electricallyconnected to the pin 95, and wire 68B is not insulated and is laserwelded or otherwise electrically connected to the case of the battery.The battery case 70 has a negative polarity. The battery's nominalvoltage is typically 3.6 V, measured during a first cycle C/5 discharge.The battery's nominal capacity, C, is no less than 2.5 mAh(milli-amp-hours) when measured after the third discharge cycle with C/2charge to 4.0V and C/5 discharge to 3.0V at 37° C. (C/2 charge meansthat it takes 2 hours for the battery 16 to charge. C/5 discharge meansthat it takes 5 hours for the battery 16 to discharge.) Charge ordischarge time is calculated by taking the capacity (mAh or Ah) anddividing it by current (mA or A). The nominal settings are 4 mAamplitude, 20 Hz pulse frequency, 200 μsec pulse width, 5 sec burst-on,5 sec burst-off, and 200 μA recovery into a 1000 Ω resistive load.

[0089] The electronic subassembly 14, shown in FIG. 1, functionstogether with the additional components of the BPB device 10, includingthe BPB case 12, BPB battery 16, and electrodes 22 and 24, to providethe BPB device stimulating function. In one preferred embodiment, theelectronic subassembly 14 fits within, for instance, a cylinder with anouter diameter D2 and length L3 as shown in FIG. 4. The inner diameterD2, has a minimum value of about 2.40 mm and a maximum value of about2.54 mm. The length L3, has a maximum value of about 13.00 mm.

[0090] The electronic subassembly 14 contains circuitry for stimulation,battery charging (when needed), telemetry, production testing, andbehavioral control. The stimulation circuitry can be further dividedinto components for high voltage generation, stimulation phase currentcontrol, recovery phase current control, charge balance control, andover voltage protection circuitry. The telemetry circuitry can befurther divided into an OOK receiver, FSK receiver, and FSK transmitter.The behavioral control circuitry can be further divided into componentsfor stimulation timing, high voltage generation closed loop control,telemetry packet handling, and battery management. In addition to thesefunctions, there is circuitry for reference voltage and referencecurrent generation, system clock generation, and Power-On Reset (POR)generation. The coil 18 (shown in FIG. 1) is utilized for receivingpower for battery charging (when used), telemetry, and high voltagegeneration.

[0091] The charging circuitry within the electronic subassembly 14detects the presence of an external charging field within no more than 5seconds of the application of such a field. Upon detection, the BPBdevice 10 enables a mode in which it can receive a telemetry message andin which it can recharge the battery 16, as necessary. The electronicsubassembly 14 measures the rectified voltage during recharging and isable to transmit the measured voltage value to the base station 50 viacoil 34. The battery voltage measurements are made in relativelyidentical conditions. Specifically, the battery voltage is measured whenno stimulation pulse is being delivered.

[0092] When the BPB device utilizes a rechargeable battery, and when thevoltage is less than the voltage defined by the Battery Recharge UpperVoltage Limit Internal Register (BRUVLIR), the BPB device 10 charges thebattery 16 using constant current charging with a maximum current ofC/2. The constant current phase of charging ends and the constantvoltage phase of charging begins when the BPB voltage reaches thevoltage defined by the BRUVLIR.

[0093] During the constant voltage phase of charging, the chargingcircuitry maintains the battery 16 charging voltage at the voltagedefined by the BRUVLIR. When the constant voltage charging current fallsto 400 μA or less (i.e., when full charge has been reached), the chargeready bit of the BPB status register is activated and charging may becompleted by the removal of the magnetic field. During charging, the BPBcharging circuitry monitors the incoming magnetic energy andperiodically sends information to the base station 50 via coil 34 inorder to minimize the magnetic field that the BPB device 10 is exposedto, thus minimizing the electrical dissipation of the BPB device 10while charging. U.S. Pat. No. 6,553,263, incorporated herein byreference, describes relevant charging technology which may also beused.

[0094] Protection circuitry within the electronic subassembly 14 is usedas a failsafe against battery over-voltage. A battery protection circuitcontinuously monitors the battery's voltage and electrically disconnectsthe battery if its voltage exceeds 4.1 V. The BPB device 10 is not ableto recover from an excessive voltage condition, and thus requiresexplantation should an over-voltage condition occur, where anover-voltage condition is defined as a voltage that exceeds 4.1 V.

[0095] The BPB device 10 has different states based on the measuredbattery voltage, Vbatt. (Vbatt is measured when no stimulation is beingdelivered). FIG. 6 represents these various states and transitionsbetween states. The BPB device 10 should normally be in Normal OperationState 102, but when the measured battery voltage, Vbatt, falls below thevoltage defined by the battery voltage hibernation level internalregister, VHIB, the device enters a low-power Hibernation State 104.VHIB is a programmable voltage value of hibernation threshold for thebattery 16. In the Hibernation State, stimulation and FSK telemetry arediscontinued. In other words, the BPB device 10 discontinues listeningfor an incoming FSK telemetry signal but continues to listen for anincoming OOK telemetry signal. In the Hibernation State 104, the BPBdevice 10 is able to detect an applied external charging field. TheHibernation State 104 persists until the battery voltage, Vbatt, exceedsthe programmable value of VHIB, where VHIB is programable between 3.25 Vand 3.6 V. The battery 16 then goes back to Normal Operation State 102and the stimulation and FSK telemetry signals resume when Vbatt becomesgreater than the programmed value ±0.05 V.

[0096] While in the Hibernation State 104, the battery 16 may also enterthe Depletion State 106 when Vbatt falls below a non-programmablevoltage value of Power On Reset (VPOR) threshold for the battery 16 ofbetween 2.2 V and 2.8V. In the Depletion State 106, the stimulation andFSK telemetry are discontinued and are only able to be resumed followingprogramming and recharging by a clinician. The BPB device 10 disablesall circuitry except what is required for recharging the battery when anRF charging field is applied. While in the Depletion State 106, the BPBcircuitry is able to recharge the battery 16 from an external chargingfield. Charging while in the Depletion State 106 is performed at a slowrate (trickle charge) to allow the battery to recover from a low voltagecondition. The BPB device 10 performs a power-on reset when Vbattexceeds VPOR, then the BPB device 10 returns back to the HibernationState 104.

[0097] The BPB device 10 can also be set in Storage Mode 108. In StorageMode 108, the BPB device 10 shuts down the circuitry in order toconserve power and the stimulation and FSK telemetry is disabled. InStorage Mode 108, the BPB device 10 is able to detect a charging fieldand is able to receive both power for recharging as well as OOKtelemetry messages via a charging field.

[0098] The BPB device 10 contains an inductive coil 18 utilized forreceiving power and telemetry messages through an inductive telemetrylink 38. The coil 18 may also be utilized to implement additionalfunctions, including voltage conversion. The BPB coil 18 contained inthe electronic subassembly 14 has an exemplary cylindrical shape and isconstructed from multiple turns of conductive wire around a two-pieceexemplary dumbbell shaped ferrite core. Assembly of the BPB coil 18,internal electronic components, and the two-piece ferrite core will bediscussed in more detail presently.

[0099] Turning back to FIG. 1, the remote control 40 provides clinicianprogramming of the BPB device 10 and limited stimulation control for thepatient following implantation via a bidirectional FSK telemetry link48. (As stated earlier, an IrDA direct link 44 is provided to interfacebetween the clinician's programmer 60 and the remote control 40.) Theremote control 40 is small and light enough to be held comfortably inone hand and fits inside a purse or pocket. Its smallest dimension is nomore than 3 cm and its largest dimension is no more than 11.5 cm. Theremote control 40 operates on standard (e.g., off-the-shelf) batteries,such as AAA batteries.

[0100] An exemplary front panel 114 of the remote control 40 is shown inFIG. 7, which identifies the primary control keys. An LCD display 116shows all values and messages, e.g., whether stimulation is enabled ordisabled or the battery's energy level or state (normal, hibernation,depletion, or storage). The following control keys are found in thefront panel 114: ON/OFF key 118, up arrow key 120, down arrow key 122,information key 123, and status key 124. All control keys are easilymanipulated and may be recessed so that they are not accidentallyactivated (e.g., when the remote control 40 is in a purse).

[0101] The Clinician's Programmer (CP) 60 controls an implanted BPBdevice 10 by communicating with an External Controller (the RemoteControl 40 or charging system 39). External Controller 39 or 40 in turnconveys commands to the BPB device 10 through an FSK telemetry link 48.A clinician has three ways to start up the CP program—“New Patient”,“Find Patient” and “Scan for BION”. The “New Patient” option brings up ablank form for the clinician to fill in the patient demographicinformation such as name, birth date, identifying number, address,contact information, and notes. The “Find Patient” option brings up amenu of previously entered patient records for selection. Upon selectionof a patient, the saved patient information is displayed for review. The“Scan for BION” option determines whether or not there is a BPB device10 within telemetry range. If so, the identification number (ID) of theBPB device 10 is obtained and the database is searched for a patientwhose implanted BPB device 10 ID matches the one found. If such a matchis found, the patient's demographic information is automaticallydisplayed for review.

[0102] Once a patient for the BPB device has been identified, theclinician can then adjust stimulation parameters through the ParameterTest utility. The successful stimulation parameter sets can be saved tothe patient's record in the database. Previously saved parameter setscan be reviewed and re-applied using utilities to view history orcurrent settings. The current battery level of the BPB device 10, aswell as records of the recharge times, can be viewed.

[0103] The Clinician's Programmer 60 may also be used to generatedifferent types of reports, such as Patient Information, SessionSummary, Implant System, and Visit History. The Patient Informationreport includes all of the patient's demographic information. TheSession Summary report summarizes the events for the followup session.The Implant System report details the information for the implanted BPBdevice 10 and any external controllers assigned to the patient. TheVisit History shows information about office visits for the patient inthe desired date range. The Clinician's Programmer 60 includes utilitiesto backup and restore the database. A utility is also available forexporting selected patient information into a data format for transfer.

[0104] As described earlier, the charging system 39 shown in FIG. 1,which includes the base station 50 and the chair pad 32, is used totranscutaneously charge the BPB battery 16 (when needed), and it is alsoused to communicate with and control the BPB device 10 via an OOKtelemetry link 38 and/or an FSK bidirectional telemetry link 48. Most ofthe electronics of charging system 39 are housed in a stand-alonepackage, with the exception of an AC adapter 54 for connection with awall AC power socket 52. The charging system 39 also provides feedbackto the user regarding the status of the BPB battery 16 duringrecharging. The remote control 40 and the clinician's programmer 60 maybe linked via an IrDA interface 45 to the charging system 39 tofacilitate exchange of data.

[0105] An exemplary manufacturing/assembly process of the BPB device 10will next be described. Unassembled BPB internal components 200 areshown in FIG. 8 and their interactions once assembled are depicted inthe functional block diagram of FIG. 21. The components 200 includepanel 202; integrated circuitry 206; capacitors 208A1, 208A2, 208B1, and208B2; diodes 210A and 210B; two ferrite halves 212A and 212B; battery16; stimulating capacitor 15; molecular sieve moisture getter material235; and unwound conductive coil wire 216. After the final assemblyprocess, the components 200 are encapsulated within, for instance, ahermetically-sealed housing which consists of two cylindrical shellhousings, e.g., a titanium housing 213 and a ceramic housing 215 (bothshown in FIG. 20B). Other suitable housing material(s) and shapes may beused.

[0106] The BPB assembly process consists of a series of assemblyoperations that, herein, are grouped into three stages. The first stagecomprises operations for putting together sub-assembly 200A (shown inFIG. 14A) and further operations to create sub-assembly 200B (shown inFIG. 15A) from sub-assembly 200A and other components; the second stagecomprises creating sub-assembly 200C (shown in FIG. 19) fromsub-assembly 200B and other components; and the third stage comprises aprocess in which the sub-assembly 200C is encapsulated within theexemplary hermetically-sealed cylindrical housing (shown in FIG. 20A).Materials used for the manufacturing/assembly process are only exemplaryand other suitable materials may be used.

[0107] With reference to FIGS. 8-16 and 21, the first assembly stagewill be described. Ten or more units may be assembled together for batchprocessing as illustrated in FIG. 9 in which the substrate panels (202A,202B, 202C, . . . herein also collectively referred to as 202 n) areshown as part of panel assembly 202. By using a batch process, startingwith the substrate panel assembly 202, the assembly procedure andtesting is more efficient as opposed to assembling each unitindividually. The substrate panel assembly 202 is a single layer,double-sided circuit board made of ceramic, organic, or other suitableflexible material(s). The contour of each panel 202 n of the substratepanel assembly 202 may be precut and only small portions of the edgesmay be left attached to the substrate panel assembly 202. The smallportions that are left intact make the alignment of other components andfuture singularization of each panel 202 n much easier, especially whenall other parts have been assembled to the substrate panel assembly 202.

[0108] As an initial assembly step, the top surface 204 of substratepanel assembly 202 is used to mount other components, such as theintegrated circuit 206, which is similar in shape to each of thesubstrate panels 202 n. The top surface 204 of the substrate panelassembly 202 is identified by a printed part number made during themanufacturing of the substrate panel assembly 202. Each panel 202 n ofsubstrate panel assembly 202 is uniquely serialized using a laser beam.The serial numbers are engraved on the bottom surface 205 of thesubstrate panel assembly 202, and metal pads 203A and 203B (shown inFIGS. 14C, 14D, and 15C) carry the serial number, which metal pads areused for test probing during several steps of the assembly process. Twoferrite half cylinders 212A and 212B “sandwich” a separated panel 202 nand associated integrated circuit 206. This “sandwich” design maximizesthe size of the half cylinders 212A and 212B and the coil 18 whichreceive the power transfer from the external coil, thus, maximizing themagnetic inductance.

[0109] The integrated circuit (IC) 206 is a custom designed IC chip. TheIC wafer, which includes a multitude of these custom ICs 206, is madeusing standard IC manufacturing processes. The IC wafer is then takenthrough a post-process called redistribution: A layer of polyimide (orother suitable insulation) is deposited on the IC surface.Photosensitive material is deposited and exposed, e.g., through a mask,in only selected areas, as in photochemical etching processes known inthe art. The photosensitive material and portions of the polyimide areremoved, for instance, to expose the aluminum pads on the surface of theIC. A layer of titanium tungsten in applied in a similar manner (i.e.,using photosensitive etching or the like) to the aluminum. A layer ofcopper is then deposited, and photochemical etching or the like used toremove the areas of copper that are not needed. This layer of copper(aided by the surrounding layers) creates the “redistribution” ofmounting pads and traces that allows secondary components such as diodes210A and 210B and capacitors 208A1 and 208A2 to be assembled above andbonded to the IC 206 and allows simplified interconnections between theIC 206 and the substrate 202 n, as shown in FIG. 13. Again usingphotochemical etching or the like, titanium tungsten or other suitablebonding material is applied to select portions of the copper, where goldor other suitable conductive material will be applied. Another layer ofpolyimide or similar insulation is applied (via photochemical etching orthe like) to select areas. A layer of gold or other conductive materialis applied (again, via photochemical etching or the like) to the bondingmaterial that was earlier applied to the copper. These added layers onthe IC surface 207 also provide a damping media for protection againstthe stresses and damages caused by assembly handling and componentplacement.

[0110] Using the top surface 204 of the substrate assembly 202 or eachsubstrate panel 202 n, a non-conductive epoxy is applied to attach eachintegrated circuit 206 as shown in FIG. 10. After the ICs 206 areassembled to substrates panels 202 n, each non-serialized IC 206 is nowuniquely identified by the serial number laser engraved on the backsideof substrate panels 202 n, and can be tested and calibrated withcalibration information saved together with the serial number.

[0111] Conductive epoxy is applied to portions of the top surface 207 ofeach IC 206 to mount, e.g., ceramic, capacitors 208A1 and 208A2, and thediodes 210A and 210B to their respective redistributed interconnectionpads, as shown in FIG. 13. Non-conductive epoxy is applied to a portionof surface 207 of the ICs 206 to attach the top ferrite half 212A, asshown in FIG. 12. Electrical wires 214 are bonded, connecting traces onpanel 202 n to diodes 210A and 210B, and connecting traces on panel 202n to IC 206. An enlarged detail view of the bonded wires 214 is shown inFIG. 13. Quality inspection can be done after this step, as well asother steps in the manufacturing process.

[0112] To protect the electrical wires 214 from any damage that mayoccur during the assembly process and handling, they may be encapsulatedwith an epoxy joint 217, as shown in FIG. 14A. The mounting of thecomponents on the top surface of the substrate panel 202 is nowcomplete.

[0113] The bottom half components of the “sandwich” ferrite arrangementare assembled next to the bottom surface 205 of the substrate panel 202n (as shown in FIG. 14B). A non-conductive epoxy is applied to theportion of the bottom surface 205 used to attach the bottom ferrite half212B. A conductive epoxy is then applied to the portion of the bottomsurface 205 of the substrate panel 202 n used to attach the ceramiccapacitors 208B1 and 208B2.

[0114] The assembled units 200A are separated from panel assembly 202 bybreaking away the pre-cut small portions made to contour the edge ofeach substrate panel 202 n. FIG. 14A shows an isometric top view of asingle sub-assembly 200A showing the wire bonds and diodes encapsulatedin epoxy joint 217. FIG. 14B shows an isometric bottom view of thesub-assembly 200A. FIG. 14C shows the top plan view of the sub-assembly200A showing the two pads 203A and 203B protruding from one end of theferrite “sandwich” arrangement. The pads 203A and 203B can be used fortesting the assembled electrical connections. The pads 203A and 203B arealso used to connect the, e.g., tantalum, stimulating capacitor 15. FIG.14D shows the bottom plan view of the sub-assembly 200A where the twopads 203A and 203B, as well as pads 201A, 201B, 201C, and 201D are alsoused for electrical test probing. The two metal pads 203C and 203D alsocarry the serial number. The bottom of the sub-assembly 200A isidentified by the mark 221 located on the ceramic capacitor 208B1 to aidin orientation and handling during manufacturing.

[0115] The unwound coil wire 216, made of 46 gauge insulated magneticcopper wire or other suitable conductive wire material, is then wound onthe middle section of the ferrite cylinder, as shown in FIG. 15A. Thecoil wire 216 in a wound configuration is referred to as the BPB coil18, as shown in FIGS. 1, 15A, and 15B. In this particular assemblyprocess, the coil 18 has 156 turns and is wound in two layers identifiedas coil layer 223A and coil layer 223B, as shown in FIG. 15B, whichdepicts a cross-section of the sub-assembly 200B (which is thedesignation given to sub-assembly 200A after it has proceeded throughthe coil winding process). One coil layer or more than two coil layersmay also be used. The required amount of layers depends on thefrequency, current, and voltage requirements. Distance A (shown in FIG.15B) is determined by the required number of coil turns and distance B(also shown in FIG. 15B) is the amount of chamfer depth required to fitthe number of layers. For this application, two layers are shown in FIG.15B. Minimizing the coil layers, which minimizes the diameter of thecoil, allows subassembly 200B to fit in the smallest shell possible, forwhich a ceramic or other suitable material can be used. As shown in FIG.15B, an exemplary “dumbbell” configuration is formed with thearrangement of the two ferrite halves 212A and 212B in which the gapformed by the distances A and B is used to wind the coil 216.

[0116] A soldering fixture 226, shown in FIG. 16, is used to assist interminating the coil ends 228A and 228B to pads 201A and 201B of thepanel 202 n, as shown in FIG. 15C. Soldering the coil ends 228A and 228Bbecomes more practical when the sub-assembly 224 is isolated and securedusing soldering fixture 226 or other similar soldering fixture. Thebottom surface of the panel 202 is facing up using the mark 221 toidentify this surface. The sub-assembly 200B is placed in fixture 226with its bottom side facing up and is held firmly in place by handle226A which is tightened by bolt 226B. FIG. 16 shows the sub-assembly200B securely loaded in soldering fixture 226. The two coil ends, 228Aand 228B, are soldered to the pads 201A and 201B (the ones next to theceramic capacitors 208B1 and 208B2 located on the bottom surface ofpanel 202), as shown in FIG. 15C. This step finalizes the first assemblystage after which sub-assembly 200B is complete.

[0117] With reference to FIGS. 17-19 and 21, the second assembly stagewill be described. A carrier 230, shown in FIG. 17, has been designed tofacilitate the second assembly stage and aid in alignment of components.The carrier 230 consists of two plates, top plate 230A and bottom plate230B. When plates 230A and 230B are bolted together, the machinedfeatures, 231A, 231B, and 231C securely hold the components assembled inthe first operation described above. The top plate 230A also containsopenings 232A, 232B, and 232C to allow access to the assembledcomponents for processing, testing, and inspection. Two bolts 234A and234B, aligned with holes 233A and 233B, are required to securely fastenplates 230A and 230B. Holes 233C and 233D are used to secure theassembled carrier 230 on a metal work plate 239 using pins 237A and 237B(shown in FIG. 18). Having the carrier 230 secured on the work plate 239facilitates in a smooth assembly process.

[0118] The sub-assembly 200B and the stimulating capacitor 15 are placedin the carrier bottom plate 230B as shown in FIG. 18, then top plate230A is bolted to bottom plate 230B with bolts 234A and 234B. Throughgroove opening 232B on top plate 230A, conductive epoxy 229 is appliedto bond the gold-coated nickel ribbon attached to one end of thecapacitor 15 to bond to pads 203A and/or 203B (seen best in FIGS. 14Cand 14D). At this point, while in the carrier 230, the assembly istested (as it is throughout the manufacturing process) and is alsoprocessed through baking temperature cycling.

[0119] The top carrier plate 230A is removed, the battery 16 is securelyplaced in the carrier groove 231C of bottom plate 230B, then top plate230A is bolted back in place. The battery 16 has two nickle wires 68Aand 68B (shown in FIG. 5) which have been pre-welded. Battery 16 isplaced into groove 231C so the nickle wires 68A and 68B protrude towardsthe bottom surface 205 of the substrate panel 202 n. Using grooveopening 232B, where the nickle wires 68A and 68B of the battery 16 andthe assembly 200B come together, an amount of non-conductive epoxy 219is applied so that the ends of wires 68A and 68B are still accessible.The nickle wires 68A and 68B are bent towards and soldered to thesubstrate pads 201C and 201D. Additional non-conductive epoxy 219 isapplied to secure the connection between the soldered nickle wires 68Aand 68B and pads 201C and 201D. This finalizes the second assembly stagewhen the sub-assembly 200C as shown in FIG. 19 is complete.

[0120] With reference to FIGS. 20A, 20B, 20C, and 21 the third assemblystage will be described. The assembly 200C is encapsulated within anexemplary hermetically-sealed housing which consists of, for instance,two cylindrical cases, a titanum 6/4 case 213 and a zirconia ceramiccase 215, as best seen in the cross sectional view FIG. 20B. Alternativematerials and shapes for the housing may also be used. A titanium 6/4 orother suitable connector 236 is brazed with a titanium nickle alloy (orother suitable material) to the ceramic case 215 for securing the matingend of the titanium case 213. The connector 236 has an inside flange236A and an outside flange 236B which serve to “self center” the brazeassembly. Before inserting the subassembly 200C and before securing themating ends, conductive silicone adhesive 238 is applied to the insideend of the ceramic shell as well as to the inside end of the titaniumshell. A molecular sieve moisture getter material 235 is also added toareas 235A, 235B, and 235C as shown in FIG. 20B before the brazingprocess.

[0121] The “spiral” self centering button electrode 22 is made fromtitanium 6/4 or other suitable material and is plated with an iridiumcoating or other suitable conductive coating. An end view of electrode22 is shown in FIG. 20C. A spiral groove 324 is made to stimulatingsurface 322 of the electrode 22. The spiral groove 324 is just oneexample of groove shapes that may be used; other shapes, such as a crosshatch pattern or other pattern may also/instead be used. Groove 324increases the conductive surface area 322 of electrode 22.

[0122] The sharp edges in groove 324 force a more homogeneous currentdistribution over the surface 322 and decrease the chances of electrodecorrosion over time. The corrosion effect which may affect the electrode22 is also known as biofouling, which is the gradual accumulation ofbacteria on the surface of the electrode 22 once immersed in body fluid.When current is injected into body fluids, an electro chemical reactionoccurs, producing large amounts of current density, which can contributeto the accumulation of bacteria. The spiral groove 324 or similar groovehelps reduce the current density along the sharp groove edges. A toolmade in the shape of a trapezoid or similar shape is used to cut thegroove 324 into a spiral or other shape. Other methods of cutting thegroove 324 may be used, e.g., ion beam etching.

[0123] The button electrode 22 becomes the active or stimulatingelectrode. A titanium/nickle alloy 240 or other suitable material isused to braze the button electrode 22 to the zirconia ceramic case 215.An end view of the BPB device 10 is shown in FIG. 20C where the end viewof the stimulating “spiral” button electrode 22 can be seen. The end 242of the titanium shell 213 is plated with an iridium coating (othersuitable conductive coating may be applied), which plated area becomesthe indifferent iridium electrode 24, as shown in FIG. 20A.

[0124]FIG. 20A shows a top view of the assembled BPB device 10 with theexternal coatings depicted. A type C parylene or other suitableinsulation coating is applied to the shaded area 244, e.g., by standardmasking and vapor deposition processes. The zirconia ceramic case isleft exposed in area 248 and the iridium electrode 24 is shown on theend 242 of the titanium case 213. This step completes the assemblyprocess of the BPB device 10. A cross-section of the final assembled BPBdevice 10 is shown in FIG. 20B.

[0125] U.S. Pat. No. 6,582,441, incorporated herein by reference,describes a surgical insertion tool which may be used for implanting theBPB device taught in this invention. The procedures taught in the '441patent for using the tool and associated components may be used forimplanting and extracting the BPB device 10 taught in the presentinvention. The surgical insertion tool described in the '441 patentfacilitates the implantation of the BPB device in a patient such thatthe stimulating electrode 22 is in very close proximity to thestimulating nerve site (e.g., near the pudendal nerve for treatingpatients with urinary urge incontinence). The proximity range may be,for example, less than 1-2 mm.

[0126] Other implantation procedures exist relating to the specific areato be stimulated. The implantable BPB device 10 may also be implanted inother nerve sites relating to preventing and/or treating variousdisorders associated with, e.g., prolonged inactivity, confinement orimmobilization of one or more muscles and/or as therapy for variouspurposes including paralyzed muscles and limbs, by providing stimulationof the cavernous nerve(s) for an effective therapy for erectile or othersexual dysfunctions, and/or by treating other disorders, e.g.,neurological disorders caused by injury or stroke.

[0127] When the power source used within the BPB device is somethingother than a rechargeable battery, e.g., a primary battery and/or one ofthe alternative power sources described previously, then the circuitrywithin the electronic subassembly 14 (FIG. 1) is modified appropriatelyto interface with, control and/or monitor the particular power sourcethat is used. For example, when the power source comprises a primarybattery, the circuitry within the electronic subassembly may besimplified to include only monitoring circuitry, not charging circuitry.Such monitoring circuitry may provide status information regarding howmuch energy remains stored within the primary battery, thereby providingthe physician and/or patient an indication relative to the remaininglife of the battery.

[0128] When the power source used within the BPB device is a supercapacitor, then such super capacitor will typically be used incombination with a primary battery and/or a rechargeable battery. Whenused in combination with a primary battery, for example, the circuitrywithin the electronic subassembly is modified appropriately so that thecharge stored on the super capacitor is available to help power the BPBdevice during times of peak power demand, such as during those timeswhen telemetry signals are being transmitted from the implanted deviceto the external device(s), or when the amplitude of the stimulationpulses has been programmed to be very high. When used in combinationwith a rechargeable battery, the circuitry within the electronicsubassembly is modified appropriately so that the charge stored on thesuper capacitor is available to help recharge the rechargeable batteryor to help power the BPB device at times of high power demand.

[0129] While the invention herein disclosed has been described by meansof specific embodiments and applications thereof, numerous modificationsand variations could be made thereto by those skilled in the art withoutdeparting from the scope of the invention set forth in the claims.

What is claimed is:
 1. An implantable electronic module, comprising: anhermetically-sealed housing having a length no greater than about 27 mmand cross-sectional dimensions no greater than about 3.3 mm; anelectronic subassembly housed within said hermetically-sealed housing;self-contained power source means contained within saidhermetically-sealed housing and operatively connected to said electronicsubassembly for providing operating power to said electronicsubassembly; a first electrode external to said hermetically-sealedhousing and electrically coupled to said electronic subassembly; asecond electrode external to said hermetically-sealed housing andelectrically coupled to said electronic subassembly; an antenna coilwithin said hermetically-sealed housing; and telemetry means, coupled tosaid antenna coil, for allowing data-containing signals to be receivedfrom and sent to an external device.
 2. The electronic module of claim 1wherein the electronic subassembly includes a ferrite core around whichthe antenna coil is wrapped.
 3. The electronic module of claim 2 whereinthe ferrite core includes a first half and a second half.
 4. Theelectronic module of claim 3 wherein the self-contained power source isselected from the group comprising: a primary battery, a rechargeablebattery, a super capacitor, a nuclear battery, a mechanical resonator,an infrared collector, a thermally-powered energy source, a flexuralpowered energy source, a bioenergy power source, a fuel cell, abioelectrical cell, and an osmotic pressure pump.
 5. The electronicmodule of claim 4 wherein the hermetically-sealed housing comprises atubular-shaped housing having a length no greater than about 27 mm and adiameter no greater than about 3.3 mm.
 6. The electronic module of claim4 wherein the electronic subassembly includes means for generatingstimulation pulses that are applied through the first and secondelectrodes.
 7. The electronic module of claim 6 wherein at least one ofthe first and second electrodes is carried on an external surface ofsaid hermetically-sealed case.
 8. The electronic module of claim 1wherein the self-contained power source means comprises a primarybattery.
 9. The electronic module of claim 5 wherein the self-containedpower source means further includes a super capacitor.
 10. Theelectronic module of claim 1 wherein the self-contained power sourcemeans comprises a rechargeable battery.
 11. The electronic module ofclaim 7 wherein the self-contained power source means further includes asuper capacitor.
 12. An implantable electronic module, comprising: anhermetically-sealed housing having a length no greater than about 27 mmand cross-sectional dimensions no greater than about 3.3 mm; anelectronic subassembly housed within said hermetically-sealed housing;self-contained power source means contained within saidhermetically-sealed housing and operatively connected to said electronicsubassembly for providing operating power to said electronicsubassembly; a first electrode external to said hermetically-sealedhousing and electrically coupled to said electronic subassembly; asecond electrode external to said hermetically-sealed housing andelectrically coupled to said electronic subassembly; and telemetry meansfor allowing data-containing signals to be received from and sent to anexternal device.
 13. The electronic module of claim 12 wherein theself-contained power source is selected from the group comprising: aprimary battery, a rechargeable battery, a super capacitor, a nuclearbattery, a mechanical resonator, an infrared collector, athermally-powered energy source, a flexural powered energy source, abioenergy power source, a fuel cell, a bioelectrical cell, and anosmotic pressure pump.
 14. The electronic module of claim 12 wherein theself-contained power source means comprises a primary battery.
 15. Theelectronic module of claim 14 wherein the self-contained power sourcemeans further includes a super capacitor.
 16. The electronic module ofclaim 12 wherein the self-contained power source means comprises arechargeable battery.
 17. The electronic module of claim 16 wherein theself-contained power source means further includes a super capacitor.18. An implantable neural stimulator module, comprising: anhermetically-sealed housing having a length no greater than about 30 mmand cross-sectional dimensions no greater than about 3.7 mm; anelectronic subassembly housed within said hermetically-sealed housing;self-contained power source means contained within saidhermetically-sealed housing and operatively connected to said electronicsubassembly for providing operating power to said electronicsubassembly; a first electrode external to said hermetically-sealedhousing and electrically coupled to said electronic subassembly; asecond electrode external to said hermetically-sealed housing andelectrically coupled to said electronic subassembly; and telemetry meansfor allowing data-containing signals to be received from and sent to anexternal device.
 19. The implantable neural stimulator module of claim18 wherein the self-contained power source means comprises a primarybattery.
 20. The implantable neural stimulator module of claim 18wherein the self-contained power source means comprises a rechargeablebattery.